1 Smoking cigarettes has been around for a long time. People smoked because they enjoyed it. Once they tried it, they were hooked. Years ago, they thought it was harmless. Smoking was believed to relieve tension. No one thought it had any ill effects. Then in the 1930s, scientists noticed that many more people had lung cancer than ever before. The American Cancer Society and others began studying the effects of smoking. In 1964, the Surgeon General reported that smoking was indeed a health hazard.2 There are over 4,000 chemicals in tobacco smoke. Many of them can start dramatic and fatal changes in the body. They include tar, carbon monoxide, metals, ammonia, and radioactive compounds.3 Scientists and doctors know so much more about the effects of smoking today than ever before. They know smoking causes immediate effects on the smoker's body. It constricts the airways of the lungs. It increases the smoker's heart rate. It elevates the blood pressure. The carbon monoxide in tobacco smoke deprives the tissues of much-needed oxygen. All of these are dangerous short-term effects.